The present invention relates to a seat structure for a chair or the like and more particularly, relates to a seat structure for a chair wherein the seat structure has a articulated portion.
Today, seats for people typically have a seat portion and a back portion which may or may not be adjustable relative to each other. Normally, both the seat portion and the back portion are rigid. As such, they do not provide any capability for movement or adjustment to a person""s body and/or seating position including the leg position. It will be understood that compatibility between a person""s body and the seat along with an ability to move therein are essential for comfort.
There have been various proposals in the art for seats with various degrees of adjustment. Thus, there are disclosed seats which have adjustable backs relative to the seat portion and as well, some of the seats have lumbar supports.
A particular type of chair having a seat portion is shown in U.S. Pat. No. 5,393,126 which teaches a composite support frame structure for the construction of a seat. The support structure comprises a rigid continuous rod like frame formed in a closed loop and which has opposed diverging rod like side members which lie in a common plane. While such a seat has received a wide degree of acceptance, it does not have any means for articulation.
Naturally, it would be desirable to provide an office type chair which has a maximum degree of comfort and adjustability since the user must occupy the chair for relatively long periods of time and the user must also be able to concentrate on their work without being distracted by uncomfortable seating. One desirable adjustment for a chair is the incorporation of a flexible area in the seat front edge upon which the user""s thighs rest. This can be particularly desirable in chairs having a tilting seat so that as the user leans back in the chair thereby tilting the seat, the leading edge of the seat is depressed downwardly to allow the user""s feet to remain on the floor.
While it has been recognized that such an adjustment is desirable and indeed there have been proposals for structures which allow the front portion of the seat to be articulated with respect to the rear portion, many of these devices require manual adjustment.
Also, many of the prior art mechanisms are costly to manufacture and assemble and incorporate complicated adjustment devices which are difficult to conceal internally to the seating unit. It is also being proposed to use foam, which is flexible, to achieve an articulation of the seat. One problem which foam presents is the breaking down of the same. Also, stretching of the fabric can present a problem. With the increased emphasis upon the visual appeal of office furniture, it is highly desirable that the controls be maintained internally to the seating unit itself.
It is an object of the present invention to provide a seat having an articulation capability.
According to one aspect of the present invention, there is provided a seat structure for a chair, the seat structure comprising a frame having a front frame section and a rear frame section, the rear frame section having a generally U shaped configuration with a rear transverse frame member and first and second rear frame side members, the front frame section having a front transverse frame member and first and second front frame side members, the first rear frame side member and the first front frame side member being joined by a first articulation means, the second rear frame side member and the second front frame side member being joined by a second articulation means, and the first and second articulation means permitting articulation of the front frame section with respect to the rear frame section, at least one of the first and second articulation means having stopper means to limit the degree of articulation of the front frame section.
In a further aspect of the invention, there is provided for an improved chair having a back, a seat, and a support structure for the seat, the improvement comprising a frame having a front frame section and a rear frame section, the rear frame section having a generally U shaped configuration with a rear transverse frame member and first and second rear frame side members, the front frame section having a front transverse frame member and first and second front frame side members, the first rear frame side member and the first front frame side member being joined by a first articulation means, the second rear frame side member and the second front frame side member being joined by a second articulation means, and the first and second articulation means permitting articulation of the front frame section with respect to the rear frame section, at least one of the first and second articulation means having stopper means to limit the degree of articulation of the front frame section.
The articulated seat of the present invention is designed for use with the type of structure shown in U.S. Pat. No. 5,393,126, the teachings of which are hereby incorporated by reference. In other words, the seat structure of the present invention is one wherein tubular elements are used for the frame of the seat structure.
The placement of the articulation means may vary although generally, it is preferred that the articulation means be between 125 mm to 175 mm from the front edge of the chair. Such a spacing has been found to provide the greatest degree of comfort.
It will be understood that the present invention may be used with different types of seats including a monocoque type frame structure and/or a structure wherein separate seats and back portions are provided.